All window covering systems have to provide a satisfactory and proper geometric fit to the window openings which they cover. While problems associated with an imperfect fit may be less critical for some window covering systems, e.g., draperies, other systems including blinds or shades require rather strict compliance with geometric fit standards. A shade that does not fit properly in its widow opening may be aesthetically deficient and therefore unacceptable. The problem is exacerbated if a poorly fitting shade affects the proper functioning of the shade. For example, a shade may be so skewed within the window opening that one side of the shade may bind against one side of the window opening while the other side of the shade may be separated from the other side of the window opening, leaving a wide, uncovered gap that precludes total privacy. In an extreme case, the shade may be skewed to the extent that it cannot be moved within its window opening without application of excessive force, which may cause damage to the shade or its mechanical components.
Generally speaking, there are three major reasons for an unsatisfactory fit of any window covering system. First, there may be imperfections in the window covering system itself. Second, there may be geometric imperfections in the window opening itself. Third, the shade system may be installed improperly. Since geometric imperfections in the window opening itself are uncontrollable, the need for proper fit adjusting mechanisms or devices and methods becomes imperative. The need is particularly significant in the installation of some modern, highly decorative window covering systems, where improper geometric fit can, in effect, completely ruin the aesthetics of the window covering system.
Roller type window shades are probably most vulnerable to proper geometric fit problems. A major reason is that even the slightest initial imperfection of geometric configuration of the shade within its window opening will be multiplied with every rotation of the shade. Errors in the geometry of the shade system, when added to window geometry imperfections and/or installation errors, result in unsightly shade systems with functioning problems as well. These aesthetic and function problems are quite annoying for the user, particularly if present in some modern, more decorative systems, such as the Silhouette Shading system developed by the Hunter Douglas Company. The Silhouette system offers several desirable features, both functional and decorative that are not found in the conventional, uncomplicated spring wound roller shade, but present difficult geometric fit considerations with extremely close tolerances that must be addressed if a satisfactory installation is to be accomplished.
Some remedies for the problems under discussion are known. For example, uneven, spiral winding of conventional roller type window shades is overcome, more or less, by biasing the downward pull on the bottom of the shade in order to straighten the travel. Similarly, a differential weight bar, used with modern Silhouette shades is intended to rectify some of their geometric fit problems. Such a single solution, however, is often completely inadequate. Its effectiveness is generally poor, as it is able to rectify only one class of its problems and to a limited degree only. What has not been done heretofore is to provide a comprehensive system of procedures and uncomplicated devices that will solve various installation and operation problems which may be encountered either separately or in combination with shade systems. Although the primary focus of the instant invention is to facilitate the installation and operation of the Silhouette shade system manufactured and marketed by the Hunter Douglas Company, several of the recommended procedures and devices herein disclosed and claimed may be used with other shade systems existing or yet to be developed ones.